Hi, Have a 4" cast iron waste drain that is off level 5/8". Was planning on using an Oatey cast iron insert flange and sanding down a spacer to level the flange. Had to replace part of bathroom floor. Now have 3/4' subfloor topped with 1/2'' plywood and 1/4" finished plywood for sheet vinyl.Do I attach the flange to the 1/2" plywood and then add the sanded spacer? Also would be interested in other ways to fix the level. Thanks

Is the pipe out of plumb, causing the flange to be out of level? Or, is the pipe plumb and the flange is cocked?

are you celebrating the 4th early, steve ?

he said the old drain is off by 5/8 inch..

anyway...
if the holes of the insert flange line up with the holes of the modified space then better to screw both dowm.
buy an extra bowl wax and smear some on the rubber ribs of the insert flange and smear the rest ontop of the insert so the spacer makes a nice sandwich. secure this to the floor.
you probably need to put the brass toilet bolts into the flange first ?
after you have secured this with stainless screws, put and extra set of washers and nuts on the bolts and snug them down fairly well.

Hi packy, Thanks for the info. Was going to use GOOP sealer between the spacer and flange. Do you have any experience using that product?

no, i have never used 'goop'.

as long as it provides a good seal then i suppose its fine.